Remove the relationEventContentModel function from ChatBarCache as ContentProvider makes it unneeded. This means turning ContentProvider into a QML singleton.
Create Message attached property to propagate parameters like room, timeline, index and maxContentWidth down to the message content avoiding lots of boilerplate
Rework ActionsHandler as static helper functions.
The functions are now invoked from ChatBarCache so there is no need to pass an actions handler object around qml simplifying the code.
{width=148 height=210}
Note: there is still an issue where after starting a new thread the threaded messages only appear after a restart as the root event needs re-downloading from the server to get the thread info added. My plan is to tackle this next.
